Conventionally, a variety of magnetic sensors have been developed. For example, Japanese Unexamined Patent Application Publication No. 2004-6752 discloses a magnetic sensor in which three or more giant magnetoresistive elements are arranged on a single substrate so as to detect the intensity of a magnetic field in three axial directions.
The magnetic sensor disclosed in the aforementioned paper is designed such that channels are formed on a silicon substrate, Z-axis giant magnetoresistive elements are arranged on slopes of channels, and X-axis giant magnetoresistive elements and Y-axis giant magnetoresistive elements are arranged on a planar surface of the silicon substrate, thus reducing the overall size thereof.
In addition, a three-axial magnetic sensor, in which elongated projections composed of silicon oxide are formed, Z-axis giant magnetoresistive elements are arranged on slopes of the elongated projections, and X-axis giant magnetoresistive elements and Y-axis giant magnetoresistive elements are arranged on a planar surface of the silicon substrate, is known.    Patent document 1: Japanese Unexamined Patent Application Publication No. 2004-6752.